My concern is having a clain denied in case of an accident or even having the policy canceled due to this "mod". I wasn't planning on slamming it to the ground, just a subtle 1"drop and refreshed suspension feel

I wouldn’t worry too much about that. I had coilovers on my last car when I got t-boned. The car was written off and I got a full claim with no questions asked. Perhaps if you had a drastic power mod and the accident was somehow related to speeding, or if your car was lowered so much it contributed to the accident damage in some major way.